Centrifugal blower and bottom housing thereof

ABSTRACT

A centrifugal blower ( 10 ) includes a bottom housing ( 12 ), a top cover ( 14 ) covering the bottom housing, and an impeller ( 16 ) and a stator accommodated in a space formed between the bottom housing and the top cover. The bottom housing includes a base plate ( 121 ), and a sidewall ( 122 ) surrounding the base plate. The sidewall includes a tongue ( 126 ) extending from the sidewall towards an inner space enclosed by an inner surface of the sidewall. The tongue is slantingly arranged with respect to a top surface ( 121   a ) of the base plate and size of a transverse section of tongue is variable changing along a height direction of the tongue.

BACKGROUND

1. Technical Field

The present invention relates to centrifugal blowers and bottom housings thereof, and more particularly to a bottom housing which helps to decrease noise generated by a centrifugal blower.

2. Description of related art

With continuing development of the electronic technology, electronic components such as CPUs generate more and more heat that is required to be dissipated immediately.

Conventionally, a centrifugal blower is used to produce an airflow which can remove heat from the electronic component. The centrifugal blower comprises a stator and an impeller being rotatable with respect to the stator. The impeller further comprises a hub and a plurality of blades radially and outwardly extending from the hub. In use, the blades of the impeller rotate around the stator to drive the airflow to flow towards the electronic component, thus cooling the electronic component continuously.

Increasing revolving speed of the impeller relatively increases the amount of airflow, therefore a heat dissipation efficiency is relatively improved. However, increasing the revolving speed may correspondingly cause a rise of a noise level generated by the centrifugal blower, thus making a user near the fan feel uncomfortable.

What is needed, therefore, is an impeller which can overcome the above-mentioned disadvantage.

SUMMARY

The present invention, in one aspect, provides a bottom housing of a centrifugal. The bottom housing includes a base plate, and a sidewall surrounding the base plate. The sidewall includes a tongue extending from the sidewall towards an inner space enclosed by an inner surface of the sidewall. The tongue is slantingly arranged with respect to a top surface of the base plate.

The present invention, in another aspect, provides a centrifugal blower using the bottom housing. The centrifugal blower includes a bottom housing, a top cover covering the bottom housing, and an impeller and a stator accommodated in a space formed between the bottom housing and the top cover. The bottom housing includes a base plate, and a sidewall surrounding the base plate. The sidewall includes a tongue extending from the sidewall towards an inner space enclosed by an inner surface of the sidewall. The tongue is slantingly arranged with respect to a top surface of the base plate.

The present invention, in a further aspect, provides a centrifugal blower using the bottom housing. The centrifugal blower includes a bottom housing, a top cover covering the bottom housing, and an impeller and a stator accommodated in a space formed between the bottom housing and the top cover. The bottom housing includes a base plate, and a sidewall surrounding the base plate. The sidewall includes a tongue extending from the sidewall towards an inner space enclosed by an inner surface of the sidewall. A size of a transverse section of tongue is variable changing along a height direction of the tongue.

Other advantages and novel features of the present impeller and centrifugal blower will become more apparent from the following detailed description of preferred embodiments when taken in conjunction with the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded, isometric view of a centrifugal blower according to a preferred embodiment of the present invention.

FIG. 2 is a top view of the centrifugal blower of FIG. 1 with a top cover being removed.

FIG. 3 is an isometric view of a bottom housing of the centrifugal blower according to a second embodiment of the present invention.

FIG. 4 is an isometric view of a bottom housing of the centrifugal blower according to a third embodiment of the present invention.

FIG. 5 is an isometric view of a bottom housing of the centrifugal blower according to a fourth embodiment of the present invention.

DETAILED DESCRIPTION

When a flow field of the airflow of a related centrifugal blower was simulated by using computational fluid dynamics (CFD) software, it was found that there were harmonic waves superposing at an area between free ends of the blades and an inner surface of a tongue formed on the centrifugal blower, which is a reason for an increase of noise generated by the centrifugal blower. After many times of experiments and tests, applicants further found that the superposition of the harmonic waves was generated due to the inner surface of the tongue perpendicular to a planar top surface of a bottom housing of the related centrifugal blower. Therefore, applicant contrives to solve such problems of the related art.

Reference will now be made to the drawing figures to describe the preferred embodiment in detail.

Referring to FIG. 1, the centrifugal blower 10 includes a bottom housing 12, a top cover 14 covering the bottom housing 12, and an impeller 16 and a stator (not shown) accommodated in a space formed between the bottom housing 12 and the top cover 14.

The bottom housing 12 includes a base plate 121 and a sidewall 122 extending upwardly from and surrounding the base plate 121. The base plate 121 of the bottom housing 12 and the top cover 14 respectively define an air inlet 123 therein. The sidewall 122 of the bottom housing 12 defines an air outlet 124 which is perpendicular to the air inlets 123. The air outlet 124 has a near side 124 a and a far side 124 b confronting to the near side 124 a. During operation of the centrifugal blower 10, airflow arrives at the air outlet 124 and flows from the near side 124 a towards the far side 124 b.

The impeller 16 includes a hub 162 and a plurality of blades 164 radially and outwardly extending from the hub 162. An air channel 125 is formed between free ends of the blades 164 and an inner surface of the sidewall 122 of the bottom housing 12. A width of the air channel 125 gradually increases along a counterclockwise direction from the far side 124 b towards the near side 124 a of the air outlet 124.

The sidewall 122 of the bottom housing 12 includes a tongue 126 near the far side 124 b of the air outlet 124. Particularly referring to FIG. 2, the tongue 126 is substantially triangular shaped in profile and integrally extends from the sidewall 122 towards an inner space enclosed by an inner surface of the sidewall 122 of the centrifugal blower 10. The tongue 126 has a first surface 126 a near the air channel 125 and the impeller 16 and is located near the far side 124 b of the air outlet 124, a second surface 126 b which faces away the air channel 125 and the impeller 16, and a third surface 126 c which smoothly and integrally connects the first surface 126 a with the second surface 126 b. The first surface 126 a is an arc-shaped surface which extends along an extension direction of the air channel 125. The second surface 126 b is substantially to be a planar surface. An extension direction of an outermost terminal end of the first surface 126 a forms an obtuse angle with an extension direction of an innermost terminal end of the second surface 126 b. Alternatively, the extension direction of the outermost terminal end of the first surface 126 a may form an acute or a right angle with the extension direction of the innermost terminal end of the second surface 126 b.

The first, second and third surfaces 126 a, 126 b, 126 c cooperatively form an inner surface 126 d of the tongue 126. The first, second and third surfaces 126 a, 126 b, 126 c of the inner surface 126 d of the tongue 126 respectively and gradually inclines towards an outer surface of the sidewall 122 of the bottom housing 12 from a bottommost end of the tongue 126 towards a topmost end of the tongue 126. That is, the inner surface 126 d of the tongue 126 is slantingly arranged with respect to a planar top surface 121 a of the base plate 121 of the bottom housing 12. A size of a transverse cross section of tongue 126 gradually decreases along a direction from the base plate 121 of the bottom housing 12 towards the top cover 14.

In the present centrifugal blower 10, the inner surface 126 d of the tongue 126 is slantingly arranged with respect to the top surface 121 a of the base plate 121 of the bottom housing 12. The slantwise inner surface 126 d of the tongue 126 disturbs the superposition of the harmonic waves and thereby decreases noise generated by the present centrifugal blower 10.

In the preferred embodiment, the size of the transverse cross section of tongue 126 gradually decreases along the direction from the base plate 121 of the bottom housing 12 towards the top cover 14. Alternatively, referring to FIG. 3, the size of the transverse section of the tongue 126 gradually increases along the direction from the base plate 121 of the bottom housing 12 towards the top cover 14. Referring to FIG. 4, the size of the transverse section of tongue 126 gradually decreases along directions respectively from an axially middle portion 126 e of the tongue 126 towards the base plate 121 of the bottom housing 12 and towards the top cover 14. Referring to FIG. 5, the size of the transverse section of tongue 126 gradually increases along directions respectively from the axially middle portion 126 e of the tongue 126 towards the base plate 121 of the bottom housing 12 and towards the top cover 14. That is, the size of the transverse section of the tongue 126 may change along a height direction of the tongue 126.

In the preferred embodiment, the inner surface 126 d of the tongue 126, i.e., the first, second and third surfaces 126 a, 126 b, 126 c of the tongue 126 are slantingly arranged with respect to the top surface 121 a of the base plate 121 of the bottom housing 12. Alternatively, there may be only one or two of the first, second and third surfaces 126 a, 126 b, 126 c of the inner surface 126 d of the tongue 126 being slantingly arranged with respect to the top surface 121 a of the base plate 121 of the bottom housing 12.

It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

1. A bottom housing of a centrifugal blower comprising: a base plate; and a sidewall surrounding the base plate, the sidewall comprising a tongue extending from the sidewall towards an inner space enclosed by an inner surface of the sidewall, the tongue being slantingly arranged with respect to a top surface of the base plate.
 2. The bottom housing of claim 1, wherein a size of a transverse section of the tongue gradually decreases along a height direction from a bottommost end towards a topmost end of the tongue.
 3. The bottom housing of claim 1, wherein a size of a transverse section of the tongue gradually increases along a height direction from a bottommost end towards a topmost end of the tongue.
 4. The bottom housing of claim 1, wherein a size of a transverse section of the tongue gradually decreases along directions respectively from an axially middle portion of the tongue towards a bottommost end and towards a topmost end of the tongue.
 5. The bottom housing of claim 1, wherein a size of a transverse section of the tongue gradually increases along directions respectively from an axially middle portion of the tongue towards a bottommost end and towards a topmost end of the tongue.
 6. A centrifugal blower comprising: a bottom housing; a top cover covering the bottom housing; and an impeller and a stator accommodated in a space formed between the bottom housing and the top cover, wherein the bottom housing comprising: a base plate; and a sidewall surrounding the base plate, the sidewall comprising a tongue extending from the sidewall towards an inner space enclosed by an inner surface of the sidewall, the tongue being slantingly arranged with respect to a top surface of the base plate.
 7. The centrifugal blower of claim 6, wherein a size of a transverse section of the tongue gradually decreases along a height direction from a bottommost end towards a topmost end of the tongue.
 8. The centrifugal blower of claim 6, wherein a size of a transverse section of the tongue gradually increases along a height direction from a bottommost end towards a topmost end of the tongue.
 9. The centrifugal blower of claim 6, wherein a size of a transverse section of the tongue gradually decreases along directions respectively from an axially middle portion of the tongue towards a bottommost end and towards a topmost end of the tongue.
 10. The centrifugal blower of claim 6, wherein a size of a transverse section of the tongue gradually increases along directions respectively from an axially middle portion of the tongue towards a bottommost end and towards a topmost end of the tongue.
 11. The centrifugal blower of claim 6, wherein the sidewall define an air outlet which comprises a near side and a far side, an airflow generated by the impeller arriving at the air outlet and flowing from the near side towards the far side, the tongue being arranged adjacent to the far side of the air outlet.
 12. A centrifugal blower comprising: a bottom housing; a top cover covering the bottom housing; and an impeller and a stator accommodated in a space formed between the bottom housing and the top cover, wherein the bottom housing comprising: a base plate; and a sidewall surrounding the base plate, the sidewall comprising a tongue extending from the sidewall towards an inner space enclosed by an inner surface of the sidewall, a size of a transverse section of tongue being variable changing along a height direction of the tongue.
 13. The centrifugal blower of claim 12, wherein the tongue has a triangular profile and comprises an inner surface which comprises a first surface adjacent to the impeller, a second surface opposite to the first surface, and a third surface connecting the first surface with the second surface.
 14. The centrifugal blower of claim 13, wherein a size of a transverse section of the tongue gradually decreases along a height direction from a bottommost end towards a topmost end of the tongue.
 15. The centrifugal blower of claim 13, wherein a size of a transverse section of the tongue gradually increases along a height direction from a bottommost end towards a topmost end of the tongue.
 16. The centrifugal blower of claim 13, wherein a size of a transverse section of the tongue gradually decreases along directions respectively from an axially middle portion of the tongue towards a bottommost end and towards a topmost end of the tongue.
 17. The centrifugal blower of claim 13, wherein a size of a transverse section of the tongue gradually increases along directions respectively from an axially middle portion of the tongue towards a bottommost end and towards a topmost end of the tongue.
 18. The centrifugal blower of claim 12, wherein the sidewall define an air outlet which comprises a near side and a far side, an airflow generated by the impeller arriving at the air outlet and flowing from the near side towards the far side, the tongue being arranged adjacent to the far side of the air outlet. 